Old thread, but in case anyone else has the problem with the radio turning itself on, I fixed mine fairly cheap. I bought a used radio with the same part number at a local salvage yard for $35. Of course when I installed it the display came up "LOCKED". The local dealer wanted $150 to reprogram the radio.
Uh, no.
Other internet sites suggested that the ghost turn on is caused by the volume knob wearing out or a spring breaking. So just for kicks I swapped the faceplate from the new radio to my old radio, and sure enough, it fixed the problem and was not locked. Apparently the security feature is in the body of the radio, and not the faceplate.
Easy swap too. Just remove one screw on each side of the faceplate, and then gently pry the top and bottom off the clips with a small flat blade screwdriver. Took about 3 minutes.